Some of the natural compounds under development for treatment of cancer are isolated from plants. In some cases, the supply of natural compounds for testing is limited by the availability of the plants from which the compound is isolated. Plant cell culture offers a methodology for increasing the availability of material from which the desired compounds can be isolated. To use this methodology, the plant cell culture must produce the compound of interest at a level approximating that found in the whole plant. By regarding antineoplastic compounds as a sub-class of species specific chemicals produced by plants, one can identify aspects of the development of plant cell cultures which are important in obtaining yields of specific chemicals to equal to or exceeding those in the whole plant. We propose to develop plant cell cultures producing the antineoplastic compound, taxol (NCS 125,973) by incorporating those aspects which are important in maintaining yields of species specific chemicals in cell cultures into the development of the cultures. This will provide a cell culture system which can be used to produce taxol. It will allow the maximum achievable yield of taxol in plant cell cultures to be determined. It will validate the general approach to achieving production of antineoplastic compounds in plant cell cultures and thus provide the basis for an alternative source of other antineoplastic compounds derived from plants.